Research has shown that, on average, more than 200,000 children are treated in U.S. hospital emergency rooms for playground-equipment-related injuries, many of which result from falls. To minimize the risks associated with playgrounds, a number of guidelines are established which require surfaces under the playgrounds to attenuate the impact of a fall.
While the primary function of a surface is often safety, the Americans' with Disabilities Act (“ADA”) also requires playgrounds be wheelchair accessible. Thus a surface must be soft enough to sufficiently attenuate the impact of a fall, while at the same time be firm, stable and slip resistant enough to comply with the ADA. Oftentimes, these two apparently conflicting requirements are reconciled by placing a solid access path to the playground structure. While such a path complies with ADA requirements, it also poses the risk that anyone falling onto the surface could result in serious injury or even death.
A combination of guidelines promulgated from both government and independent bodies tackle the tricky issue of providing surfaces at play grounds that are soft enough to prevent most fall injuries but that are also firm and stable enough for wheelchair maneuvering. For example, the guidelines, based on American Society for Testing and Materials (ASTM) standards, state that wheelchair access, surfaces are required to be “firm, stable and slip resistant” as specified in Americans with Disabilities Act Accessibility Guidelines (ADAAG). Another example is the amount of force required to rotate the caster wheels of a wheel chair as set for in ASTM standard F-1951, which is based on a measurement of the physical effort to maneuver a wheelchair across a surface. Accessible surfaces within the use zone (the ground level area beneath and immediately adjacent to a play structure) are also required to be “impact attenuating” in compliance with ASTM F-1292 requirements for drop testing.
Materials currently used as impact-absorbing surfaces under playgrounds include sand and gravel, shredded tires, poured rubber to name a few. Sand and gravel have been traditionally used because of their impact attenuation properties, wide availability and low cost. However, such a surface is not wheelchair accessible. In addition, sand and gravel tends to lump and harden when wet or frozen. In addition, the critical fall height for sand and gravel is merely nine feet, which is reduced to five feet when the sand or gravel is compressed. Furthermore, such a surface can cause abrasions when a playground patron falls, can cause a patron to trip when running, is tracked indoors and can cause scratches on floors, can be thrown, can be blown away with wind, as well as be an attraction for cats and other animals. Thus, sand and gravel are not ideal materials to use for playground purposes.
Alternatively, shredded tires are used, however, these pose additional problems of becoming very hot when in direct sunlight, being flammable, and containing steel belts that were part of the original tire. Additionally, shredded tire installations, when properly installed to attenuate falls, do not meet the requirements for accessibility as defined in ASTM F-1959.
Similarly, poured rubber is used because it is wheelchair accessible, however, it is expensive to purchase and install. In addition, as the rubber wears out under high traffic areas such as swings, the rubber cannot be replaced without significant additional expense. Furthermore, several obstacles arise during installation such as bonding the rubber to the cement base or ground arid requiring completely level ground when the rubber is poured. Poured rubber is also prone to cracking and mechanical failure if exposed to ultraviolet light, extreme temperatures or water. There is evidence that, when exposed to environmental factors over time, a poured surface may deteriorate to the point where it will fail ASTM F-1292 testing.
Matching the appropriate surface and application can also pose problems. For example, a pool and its surround deck are often made of cement which can get very slick when wet, and a fall thereon may cause a serious injury. Similarly an injury may result from a person diving into and hitting the bottom of a cement pool. Alternatively a cement surface can be so abrasive so as to cause blisters or cuts on swimmers' feet.
Given the known hazards and limitations of existing surfaces, an impact-attenuating surface, which is also firm, stable, and slip-resistant in accordance with the ADA, would be beneficial.